Why is my air conditioner not cooling but the fan is running?

When your AC blows air but doesn't cool, the compressor may be off, the condenser coils dirty, or the refrigerant low. Diagnose step by step.

Category:HVAC

Difficulty:Moderate

Time:30 min

Success:50%

Updated:Jun 15, 2026

quick_referenceQuick Answer

For Why is my air conditioner not cooling but the fan is running?, start with "Check the outdoor unit breaker": Go to your electrical panel and find the double-pole breaker for the AC. If it's tripped (midway between on and off), flip it fully off, then fully on. Stop DIY if the compressor hums loudly and then trips the breaker immediately. This is listed as a moderate recovery and usually takes about 30 min.

verifiedGuide Snapshot

Repair areaHVAC

Estimated time30 min

DifficultyModerate

Stop conditions3

Last updated Jun 15, 2026. Review the stop conditions before continuing.

account_treeRecovery State

DeviceAc Unit

Current stateInsufficient Cooling

Specific stateFan Runs No Cooling

Failed stepCompressor Not Starting

Likely failure typeElectrical Fault

DIY boundaryDIY recovery first

paymentsCost decision

help1. Understand the Problem

A central AC unit that runs the fan but delivers warm air usually means the compressor outside isn't kicking on. This can be caused by a tripped breaker, a bad capacitor, dirty condenser coils, or low refrigerant. The indoor fan will continue to blow even if the compressor fails, so you'll feel air movement without cooling.

build_circle2. Try This First

Best First Step

Check the outdoor unit breaker

Go to your electrical panel and find the double-pole breaker for the AC. If it's tripped (midway between on and off), flip it fully off, then fully on.

visibility3. Visual Guidance

See what's happening and how to try the first recovery step.

Inspect the condenser unit for debrisTurn off power at the breaker. Remove the side panel of the outdoor unit. Use a vacuum with a brush attachment to clean dirt and leaves from the coil fins.

Test the run capacitorLocate the cylindrical capacitor inside the access panel. If the top is bulging or leaking, it's bad. Use a multimeter to check capacitance (should match printed value).

Listen for compressor humRestore power. Stand near the outdoor unit and listen. If you hear a loud hum for 5 seconds then a click, the capacitor is likely failed. If no sound at all, check the contactor.

autorenew4. If That Doesn't Work

Try the next recovery options.

Call a professional for refrigerant rechargeIf the compressor runs but the air isn't cold, you likely have a refrigerant leak. This requires EPA-certified handling and professional repair.

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